This invention relates to test and measurement, and more particularly to test instruments for optical time domain reflectometry (OTDR).
Two types of fibers are in typical use in optical fiber communications, singlemode and multimode fibers. Singlemode fibers employ a more narrow core (relative to multimode) wherein light rays travel therethrough as single rays. Multimode fibers have a larger diameter and light propagates therethrough in multiple rays.
Typically, singlemode fiber systems employ light sources at 1310 nm and 1550 nm, while multimode fiber systems employ light sources of 850 nm and 1300 nm.
OTDR testing of fiber optic communication systems is employed to locate and characterize reflective and loss events in optical fibers. In accordance with the prior art, to provide testing capability of optical time domain reflectometry to test both singlemode and multimode fiber systems, test instrument costs become prohibitive because of required redundancy in electro-optic components.